Manufacturing method for a composite metal bonding wire and products thereof

ABSTRACT

A manufacturing method for a composite metal bonding wire and products thereof. A material of Ag and Au is co-melted in a vacuum melting furnace, and then a plurality of trace metal elements are added into the vacuum melting furnace and co-melted with the material to obtain a composite metal ingot. The obtained composite metal ingot is drawn to obtain a composite metal wire. The composite metal wire is then drawn to obtain a composite metal bonding wire with a predetermined diameter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a bonding wire used as a packaging wire, in particular, to a manufacturing method for a composite metal boding wire and products thereof.

2. Description of Prior Art

In semiconductor packaging processes for IC, LED, SAW, a wire bonding process is performed to electrically connect the chip to the substrate by bonding wire, which used as a signal and electrical current transmitting medium between the chip and the substrate.

The specification of a bonding wire is based on the type of the packaging process. The specification of a bonding wire, such as breaking load, elongation, loop, melting point, are dependent on the materials used as the bonding wire. The performance of the packaged semiconductor device is influenced by the specification of the bonding wire. Therefore, the wire bonding material selected for a semiconductor packaging process is usually featured by its high elongation property and stability.

The two categories of bonding wires usually selected for conventional semiconductor packaging processes are pure Au bonding wire and Al—Si bonding wire. Pure Au bonding wire has better physical properties, such as elongation and electrical conductivity. However, pure Au bonding wire inevitably leads to high cost. Therefore, the purpose of the present invention is to provide a low cost bonding wire with performance comparable to pure Au bonding wire.

SUMMARY OF THE INVENTION

The purpose of this invention is to provide a low cost composite metal bonding wire with performance as good as a pure Au bonding wire.

In order to obtain the purpose mentioned above, a manufacturing method for a composite metal bonding wire and products thereof is disclosed. Ag and Au materials are co-melted in a vacuum melting furnace, and then a plurality of trace metal elements are added into the vacuum melting furnace and co-melted with Ag and Au materials to obtain a composite metal ingot. The obtained composite metal ingot is then drawn to obtain a composite metal wire. Finally, the obtained composite metal wire is then drawn to obtain a composite metal bonding wire with a predetermined diameter.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart for manufacturing composite metal wire of the present invention; and

FIG. 2 shows detailed sub-steps in the flow chart of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

In cooperation with attached drawings, the technical contents and detailed description of the present invention are described thereinafter according to a preferable embodiment, being not used to limit its executing scope. Any equivalent variation and modification made according to appended claims is all covered by the claims claimed by the present invention.

Please refer to FIG. 1 and FIG. 2, which respectively are a flow chart for manufacturing composite metal wire of the present invention and a drawing showing detailed sub-steps in the flow chart of FIG. 1. Step 100, a material of Ag and Au is provided.

Step 102, a material of Ag and Au is co-melted in a vacuum melting furnace (step 102 a). Specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace (step 102 b), and co-melted with the material of Ag and Au in the vacuum melting furnace to obtain a composite metal ingot (step 102 c). The composite metal ingot consists of 90.00˜99.99% Ag, 0.00001˜9.99997% Au, 0.00001˜2.99997% Cu, 0.00001˜2.99997% Be and 0.00001˜2.99997% Al.

Subsequently, continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with diameter of 4-8 mm (step 102 d). The composite metal wire is rewired by a reeling machine (step 102 e) and then composition analysis (102 f) is performed on the composite metal wire to check if the obtained composition meets the requirement.

Step 104, a drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 4-8 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 3 mm or smaller than 3 mm (step 104 a). The composite metal wire with a diameter of 3 mm or smaller than 3 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a predetermined diameter of 1 mm or smaller than 1 mm (step 104 b). The composite metal wire with diameter 1 mm or smaller than 1 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.5 mm or smaller than 0.5 mm (step 104 c). Then the composite metal wire with a diameter of 0.5 mm or smaller than 0.5 mm is sequentially drawn by the second thin drawing machine (step 104 d), a very thin drawing machine (step 104 e) and an ultra thin drawing machine (step 104 f) to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Step 106, the surface of composite metal bonding wire is cleaned.

Step 108, the composite metal bonding wire is annealed to ensure a final product with desirable physical properties of breaking load and elongation.

The composite metal bonding wire can be applied to packaging process of IC, LED and SAW.

The invention is more detailed described by seven embodiments below:

EMBODIMENT 1

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 98.659% Ag, 0.5% Au, 0.84% Cu, 0.0008% Be and 0.0002% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 6 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 3 mm. The composite metal wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 1 mm. The composite metal wire with a diameter of 1 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.5 mm. Then the composite metal wire with a diameter of 0.5 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

EMBODIMENT 2

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 99.99% Ag, 0.005% Au, 0.003% Cu, 0.001% Be and 0.001% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 6 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 3 mm. The composite metal wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 0.8 mm. The composite metal wire with a diameter of 0.8 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.45 mm. Then the composite metal wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

EMBODIMENT 3

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 95% Ag, 1.25% Au, 1.25% Cu, 1.25% Be and 1.25% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 6 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 3 mm. The composite metal wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 0.9 mm. The composite metal wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.45 mm. Then the composite metal wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

EMBODIMENT 4

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 97% Ag, 0.00001% Au, 0.00001% Cu, 2.99997% Be and 0.00001% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 4 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 4 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 2.5 mm. The composite metal wire with a diameter of 2.5 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 0.9 mm. The composite metal wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.45 mm. Then the composite metal wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

EMBODIMENT 5

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 90% Ag, 9.99997% Au, 0.00001% Cu, 0.00001% Be and 0.00001% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 8 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 8 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 2 mm. The composite metal wire with a diameter of 2 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 0.9 mm. The composite metal wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.45 mm. Then the composite metal wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

EMBODIMENT 6

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 97% Ag, 0.00001% Au, 0.00001% Cu, 0.00001% Be and 2.99997% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 6 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 3 mm. The composite metal wire with a diameter of 3 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 0.9 mm. The composite metal wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.45 mm. Then the composite metal wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

EMBODIMENT 7

A material with Ag and Au is provided and is co-melted in a vacuum melting furnace. Then, specific amounts of trace metal elements Cu, Be and Al are added into the vacuum melting furnace, and co-melted with the material in the vacuum melting furnace to obtain a composite metal ingot. The composite metal ingot consists of: 97% Ag, 0.00001% Au, 2.99997% Cu, 0.00001% Be and 0.00001% Al.

Continuous casting process is performed on the composite metal ingot to draw to obtain a composite metal wire with a diameter of 6 mm. The composite metal wire is rewired by a reeling machine and then composition analysis is performed on the composite metal wire to check if the obtained composition meets the requirement.

A drawing process is performed on the composite metal wire, the obtained composite metal wire with a diameter of 6 mm is drawn by a first thick drawing machine to obtain a composite metal wire with a diameter of 2 mm. The composite metal wire with a diameter of 2 mm is drawn by a second thick drawing machine to obtain a composite metal wire with a diameter of 0.9 mm. The composite metal wire with a diameter of 0.9 mm is drawn by a first thin drawing machine to obtain a composite metal wire with a diameter of 0.45 mm. Then the composite metal wire with a diameter of 0.45 mm is sequentially drawn by the second thin drawing machine, a very thin drawing machine and an ultra thin drawing machine to obtain an ultra thin composite metal bonding wire with a predetermined diameter of 0.0508 mm (2.00 mil) or 0.010 (0.40 mil).

Finally, the surface of composite metal bonding wire is cleaned and is annealed.

While the invention is described in by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, the aim is to cover all modifications, alternatives and equivalents falling within the spirit and scope of the invention as defined by the appended claims. 

1. A manufacturing method for a composite metal bonding wire, comprising: a) providing a material of Ag and Au; b) co-melting the material in a vacuum melting furnace, adding a plurality of trace metal elements into the vacuum melting furnace and co-melting with the material in the vacuum melting furnace to obtain a composite metal ingot; c) drawing the composite metal ingot to obtain a composite metal wire; and d) drawing the composite metal wire to obtain a composite metal bonding wire with a predetermined diameter.
 2. The manufacturing method according to claim 1, wherein the mass fraction of Ag in step a) is 90.00%˜99.99% and the mass fraction of Au is 0.00001%˜9.99997%.
 3. The manufacturing method according to claim 2, wherein the trace metal elements in step b) comprises 0.00001%˜2.99997% Cu.
 4. The manufacturing method according to claim 3, wherein the trace metal elements in step b) comprises 0.00001%˜2.99997% Be.
 5. The manufacturing method according to claim 4, wherein the trace metal elements in step b) comprises 0.00001%˜2.99997% Al.
 6. The manufacturing method according to claim 1, wherein the surface of the composite metal bonding wire is cleaned and is annealed after step d).
 7. A composite metal bonding wire, comprising: 90.00˜99.99% Ag; and 0.00001˜9.99997% Au.
 8. The composite metal bonding wire according to claim 7, further comprises 0.00001%˜2.99997% Cu.
 9. The composite metal bonding wire according to claim 8, further comprises 0.00001%˜2.99997% Be.
 10. The composite metal bonding wire according to claim 9, further comprises 0.00001%˜2.99997% Al. 